The performance and correct pressure for the inlet manifold is given in the Fuel Setting and Related Information in the TMI. Development of this information is done with these conditions:
- The dry barometric pressure measures
96 kPa (28.8 inches Hg) . - 25 °C (77 °F) outside air temperature
- 35 API rated fuel
Any change from these conditions can change the pressure in the inlet manifold. The outside air may have a higher temperature and a lower barometric pressure than the values that are given above. This will cause a lower inlet manifold pressure measurement than the pressure that is given in the TMI. Outside air that has a lower temperature and a higher barometric pressure will cause a higher inlet manifold pressure measurement.
A difference in fuel density will change horsepower and boost. If the fuel is rated above 35 API, the pressure in the inlet manifold can be less than the pressure that is given in the TMI. If the fuel is rated below 35 API, the pressure in the inlet manifold can be more than the pressure that is given in the TMI.
Be sure that the air inlet or the exhaust does not have a restriction when you are making a check of the pressure.
Note: The electronic service tool may be used to check the pressure in the inlet manifold.